Henry George Liddell, Robert Scott, A Greek-English Lexicon

A.“πτυ^χί” Il. 20.22: pl. πτύχες, πτύχας, 7.247, al., Hes.Sc.143, etc.: after Hom. πτυ^χή , ῆς, which prevails in Pi. (v. infr. 11) and Trag.; the metre requires acc. sg. πτύχα in E.Supp.979 (lyr.), but acc. pl. πτυχάς in S.Fr.144; in other places either πτύχας or πτυχάς will suit the metre:—poet. word, layer, plate, mostly in pl., σάκεος πτύχες plates of metal or leather, in strong shields, Il.18.481, cf. 7.247, 20.269, Hes.Sc.143.

2. fold (i.e.folded piece) of a garment, in pl., first in h.Cer.176, then in S.Fr.494, E.Supp.979 (lyr.); of the entrails, κατὰ σπλάγχνων πτυχάς ib.212; “εἰς τὰς πτυχάς” Arist.HA549a17; coats of the stomach, Gal.2.556; layers of muscles, Id.18(2).944.

3. writing tablets, “ἐν πτυχαῖς βίβλων κατεσφραγισμένα” A.Supp.947; “γραμμάτων πτυχὰς ἔχων” S.Fr.144; “ἐν δέλτου πτυχαῖς” E.IA98, cf. IG9 (1).880.10 (Corc.).

II. in hilly country, folds, glens, “κατὰ πτύχας Οὐλύμποιο” Il.11.77; πτύχες ἠνεμόεσσαι (from the wind that rushes down narrow mountain-clefts), Od.19.432; also in sg., πτυχὶ Οὐλύμποιο, Παρνησοῖο, Il.20.22, h.Ap.269, h.Merc.555; πτυχαὶ Κρισαῖαι, Πίνδου, Πέλοπος, Pi.P.6.18,9.15, N.2.21; “ἐν Κιθαιρῶνος πτυχαῖς” S.OT 1026, cf. E.Supp.757, Ba.62, Andr.1277; “Αὐλίδος κατὰ πτυχάς” Id.IT1082, cf. 9: also of the sky, πτυχαὶ αἰθέρος, οὐρανοῦ, Id.Or.1631, Hel.44, Ph.84: sg., “μέχρις οὐρανοῦ πτυχός” Ezek.Exag.69.

III. metaph., ὕμνων πτυχαί folds of song, i.e. sinuous songs, Pi.O.1.105.

IV. acc. pl. πτυχάς or πτύχας leaves of a folding door, metaph., ὁ κλείσας οὐρανοῦ δισσὰς π. PMag.Par.1.190; nom. πτύχες, = θύραι, σανίδες, Poll.10.24.

V. πτυχή, ἡ, the part of a ship on which her name was inscribed, Sch. A.R. 1.1089; cf. πτυχίς.